Spinal fixation devices are used in orthopedic surgery to align and/or fix a desired relationship between adjacent vertebral bodies. Pedicle screw assemblies, for example, typically include a screw having a threaded shank that is adapted to be threaded into a vertebra, and a head portion having a rod-receiving element, usually in the form of a U-shaped slot formed in the head. A set-screw, plug, or similar type of fastening mechanism, is used to lock a fixation rod seated in the rod-receiving head of the pedicle screw to securely interconnect each screw and the fixation rod.
Rod reduction is often necessary to position and hold the rod against the seat of the rod-receiver. Rod persuader instruments that are used to perform rod reduction must apply sufficient force to position the rod in the receiver of the pedicle screw. Some rod persuader instruments are actuated by articulating handles that extend laterally from the main shaft of the instrument. This can add undesired weight to the instrument and create a visual obstruction over the implant site. Other rod persuader instruments require constant force to be applied manually on the actuator to hold the rod in the seated position while the set screw is manipulated. This limits the use of one hand when the set screw is being inserted and tightened into place. In addition, it can be difficult to align and seat the rod into the rod-receiver of adjacent fixation devices due to the positioning and rigidity of the vertebra into which the fixation device is mounted.
Accordingly, there is a need for improved rod reduction devices and methods for seating a spinal rod, or other spinal fixation element, into one or more spinal implants or fasteners.